The present invention relates to a 3-dimensional data preparing method and a 3-dimensional data preparing device using GPS (Global Positioning System), in case position measurement by GPS cannot be successfully achieved.
In recent years, position measurement using GPS has been increasingly propagated. For example, In case that civil engineering work is carried out by using civil engineering construction machine such as bulldozer, the working position, i.e. the position of the bulldozer, is determined, and the like, by a GPS position detecting device, and the working position is confirmed. Or, an electronized map information as in a car navigator is linked with position data of a mobile object obtained by the GPS position detecting device, and the present position is reflected on an electronic map and is turned to an image, and the present position is displayed, and the like, on an image display device. In this way, it is possible to measure the position of a mobile object at real time.
In case that civil engineering work is carried out by a civil engineering construction machine, it is preferable to obtain 3-dimensional data of the working position or 3-dimensional data of a scheduled working position to match the construction data for the purpose of carrying out civil engineering work with high accuracy.
Under such condition that the image processing technique is progressing and that capacity of the storage device is becoming larger, there are now strong demands on 3-dimensional display of topography and scenes to facilitate more visual judgment for the function of electronic map. Also, it is now wanted to acquire images with 3-dimensional data in easier manner and in large amount as map data.
However, electric wave from satellite is used in the position measurement by GPS. The electric wave from the satellite is interrupted by an obstacle, e.g. by a mountain, a building, etc., and then, there is a place (a shade) where electric wave does not reach. Therefore, in the place of the shade, position measurement cannot be performed by GPS.
In the past, for the place or the section where position measurement cannot be performed by GPS, it was necessary to stop the operation and to be performed surveying operation by human power using conventional type surveying instrument.
Or, as the map data of the place of shade, only image data without position data and/or planar image data can be acquired. There have been inconveniences that, for instance, electronic map cannot be displayed, and the like, by continuous 3-dimensional image.